WO2023144923A1 - Control device and processing equipment - Google Patents

Abstract

A control device 1 is provided with: a motor control unit (10, 11, etc.) that supplies a drive current to a motor 3, which is a power source of processing equipment, so as to place the motor 3 in a normal operating state, and, in response to multiplexed commands (S1, S2) that are sent from the outside and relate to a safety function operation of the processing equipment, controls the drive current so as to place the motor 3 and the processing equipment in a safety stop state; and a command monitoring unit 16 that monitors whether or not the commands (High/Low of S1, S2) match each other. If the period during which the commands do not match exceeds an allowable value, the command monitoring unit 16 generates a safety stop signal Sd (High) for safely stopping the motor 3, and continuously sends the safety stop signal Sd (High) to the motor control unit. This configuration makes it possible to facilitate the construction of a safety system that uses a control device.

Description

Controller and processing equipment

The present disclosure relates to control devices and processing equipment, and in one non-limiting specific example, to control devices that control the operation of motors in various processing equipment or machine drive systems that are equipped with motors.

In the field of various processing equipment equipped with motors (e.g. injection molding machines, press machines), in order to ensure the safety of the processing equipment and the surrounding environment, etc., a safe stop function that controls to safely stop the motor of the equipment (hereinafter sometimes abbreviated as "safety function") must be provided. Specifically, the control for safely stopping the motor includes various types of control such as torque-off stop and deceleration stop. This control is executed based on a signal (sometimes called a safety signal or the like) from an external device provided outside the device.

As a conventional example of torque-off control of a motor, there is, for example, the technology described in Patent Document 1 below. Patent Literature 1 describes a power converter with an STO (safe torque off) function. In addition, the safety functions of mechanical drive systems using motors are internationally standardized, and the above STO is one of the internationally standardized (defined) safety functions. The STO function can be said to be a function for forcibly interrupting the torque of the motor.

On the other hand, the specific configuration of each block such as input, output, and monitoring in the safety function is not standardized, so it is left to individual product design.

JP-A-2011-8642

By the way, in order to strengthen the safety function, in individual product design, the safety signal from the external device and the path of the signal (safety route) are duplicated, and the same safety signal is output from the external device at the same time. It is conceivable to configure With such a configuration, even if a failure occurs in one of the safety paths, control for safely stopping the motor can be executed.

Double safety path monitoring can be realized, for example, by externally monitoring the operating state of the output block that outputs control signals to the motor drive circuit. On the other hand, when this is applied to industrial machine systems that use multiple-axis motors and their control devices, such as servo press machines and plastic processing machines, the burden of monitoring increases in the host system, and the failure rate due to wiring etc. increases. I have a problem.

An object of the present invention is to facilitate the construction of a safety system in an industrial machine in which the motor is used by incorporating a monitoring function for a multiple system safety system and a protection function according to the monitoring result into a control system that drives and controls the motor. It is to be.

In order to achieve the above objects, the present invention employs the configurations and methods described in the claims. As an example, the control device of the present invention is

A motor that puts the motor into a normal operation state by sending a drive current to the motor, and controls the motor so that the normal operation state goes into a safe stop state in response to a multiple command related to safety function operation sent from the outside. a control unit;
a command monitoring unit that monitors whether the commands match each other;

The command monitoring unit generates a safe stop command for safely stopping the motor when a period in which the commands do not match each other exceeds an allowable value, and continuously sends the generated safe stop command to the motor control unit. Send out.

According to the present invention, it is possible to easily construct a safety system in an industrial machine system that uses a motor.

1 is a circuit diagram showing a configuration of a motor control device according to Embodiment 1 of the present disclosure; FIG. 2 is a circuit diagram showing one specific example of a safe torque off (STO) circuit of FIG. 1; FIG. 2 is a circuit diagram showing one specific example of the safety monitoring circuit of FIG. 1; FIG. FIG. 5 is a circuit diagram showing an example of a safe torque-off circuit according to Embodiment 2 of the present disclosure; FIG. 7 is a circuit diagram showing the configuration of a motor control device according to Embodiment 3 of the present disclosure; FIG. 5 is an example of a safety input circuit according to Embodiment 4 of the present disclosure; FIG. FIG. 11 is a circuit diagram illustrating the configuration of a motor control device according to Embodiment 5 of the present disclosure; FIG. 11 is a circuit diagram showing another specific example of a safety control block and a safe torque-off circuit according to Embodiment 6 of the present disclosure; FIG. 11 is a circuit diagram showing another specific example of a safety control block and a safe torque-off circuit according to Embodiment 7 of the present disclosure;

<Outline configuration>
Hereinafter, before describing each embodiment of the present disclosure, general contents common to each embodiment will be described with reference to the drawings as appropriate. The processing equipment system described below is mainly composed of a combination of the following devices (1) to (3).

(1) Motor control device (indicated by symbols 1, 1A, and 1B in FIGS. 1, 5, and 7; symbol 1 is used representatively below.)

The motor control device 1 is a device for controlling the operation (rotation start/stop, rotation direction, rotation speed, etc.) of an electric motor (hereinafter simply referred to as a motor) 3 used as a power source for processing equipment. It is a main device (control device) in the disclosed processing equipment system. The motor control device 1 comprises various functional block units as shown in FIGS. 1, 5 and 7 in order to control the operation of the motor 3 and the machining equipment in which the motor 3 is used.

The processing equipment that uses the motor 3 and the motor control device 1 is not particularly limited, and examples thereof include various industrial equipment such as plastic processing machines such as servo press machines and injection molding machines.

(2) External safety device (indicated by symbols 2 and 2A in FIGS. 1, 5, and 7; symbol 2 is used representatively below.)

The external safety device 2 monitors the operation of the motor 3 or the processing equipment, generates multiple commands (arbitrary number of signals indicating the same content for Lo/High) regarding the safety function operation of the processing equipment, and generates multiplex command to the motor control device 1 through the transmission system.

As shown, the external safety device 2 is an external device separate from the motor control device 1. In this example, the motor control device 1 is connected via multiple (double in each figure) signal lines and a wired interface. connected with The connection between the motor control device 1 and the external safety device 2 may be partially or wholly replaced by communication means (wireless interface). The external safety device 2 can also be called a safety function unit. Further, a transmission system (wired or wireless interface, etc.) for multiple commands sent from the external safety device 2 (safety function section) to the motor control device 1 can be called a safety signal transmission section.

When these external safety devices 2 detect an abnormality in the operation of the motor 3 or the processing equipment, a stop command (e.g., a predefined signal (e.g., Low or High signal) to the motor control device 1. On the other hand, if the external safety device 2 does not detect any abnormality in the operation of the motor 3 or the processing equipment, the control of the motor 3 by the motor control device 1 is executed as it is. is sent (input) to the motor control device 1. In each figure and below, the above-described stop command and execution command are collectively referred to as safety input signals S1 and S2. .

The configuration of the safety function unit (external safety device 2), which is an external device, and the method of detecting anomalies, etc., are well known, and detailed description thereof will be omitted as appropriate.

(3) Safety monitoring device (indicated by reference numeral 16 in Figures 1, 5 and 7)

The safety monitoring device 16 checks that the contents of the multiple safety input signals S1 and S2 sent (inputted) from the external safety device 2 to the motor control device 1 (instructions, ie Lo/High states) match each other. It is a device that plays a role as a "command monitoring unit" that monitors. In the illustrated example, the safety monitoring device 16 inputs multiple safety input signals S1 and S2 through branch lines of the signal lines through which the safety input signals S1 and S2 are transmitted, and outputs the content of the input signal (command ) are compared to monitor and eventually diagnose, and a signal indicating the diagnosis result is output to the motor control device. Hereinafter, the signal indicating this diagnosis result will be referred to as "diagnosis protection signal Sd".

When the commands (Lo/High) included in the multiple safety input signals (S1, S2) output from the external safety device 2 match each other, the safety monitoring device 16 outputs the diagnosis protection signal Sd. Description will be made on the assumption that a Lo signal is output, and if they do not match, a High signal is output as the diagnostic protection signal Sd.

Next, the technical significance of the safety monitoring device 16 will be explained in relation to other devices. The motor control device 1 described in (1) normally sends a drive current to the motor 3, thereby controlling the motor 3 and the machining equipment so as to perform operations and functions according to the purpose. Hereinafter, this state may be referred to as a "normal operating state". Further, since the operation of the motor 3 and the processing equipment in the normal operating state is well known, detailed description thereof will be omitted.

On the other hand, the motor control device 1 performs control such as reducing or cutting off the drive current sent to the motor 3 when the stop command (for example, Lo signal) is input from the above (2), that is, the external safety device 2. to safely stop the motor 3 and the processing equipment. By performing such control, the motor 3 (processing equipment) can be shifted from a normal operation state to a safe stop (torque off or deceleration stop) state.

The significance of sending multiple commands (safety input signals S1 and S2) from the external safety device 2 to the motor control device 1 is to enhance safety protection. More specifically, for example, when a stop command and an execution command are sent from the external safety device 2 to the motor control device 1 through two signal lines, one of the signal transmission systems (circuits, signal lines, radio wave state, etc.), the command (safety input signal) can be transmitted through the remaining signal transmission system even if the command cannot be transmitted.

Therefore, the motor control device 1 enters a safe stop state when a safety input signal (S1 or S2) indicating a stop command is input from any of the signal transmission systems of the external safety device 2 in the above normal operation state. In order to shift, the same control as described above is performed to safely stop the motor 3 and the processing equipment. In this way, safety protection is strengthened by adopting a configuration in which safe stop control is performed in accordance with a stop command input from any of the signal transmission systems.

On the other hand, as described above, if one of the signal transmission systems of the external safety device 2 breaks down and the processing equipment continues to operate while this is left unattended, the enhancement of safety protection described above becomes a mere avail. In addition, if a further failure occurs in the external safety device 2, the motor control device 1 may not be able to control the safe stop. Such cases are likely to occur when, for example, a Lo signal is assigned to an execution command and a High signal is assigned to a stop command. For this reason, the following is premised on the reverse, that is, a configuration in which the High signal is assigned to the execution command and the Lo signal is assigned to the stop command as the safety input signals S1 and S2. With such a configuration, when trouble such as disconnection occurs in one of the signal transmission systems, the signal (command) of the signal transmission system becomes Lo, which has the advantage of facilitating detection of various troubles. it is conceivable that.

On the other hand, even if there is no disconnection in any signal transmission system of the external safety device 2 and the safety input signals S1 and S2 (Lo/High commands) are generally sent normally, the phase (for example, execution command timing to switch to the stop command) may occur. In this case, the motor control device 1 performs safe stop control in response to the earlier sent stop command from the safety point of view. However, if the stop command signal to which the response is made is an erroneous signal based on a malfunction of the external safety device 2, etc., there are disadvantages associated with the timing of performing a safe stop being too early (e.g. lowering the quality, etc.) may occur.

Therefore, in the processing equipment system, multiple commands (Lo/High) sent (input) from the safety monitoring device 16 described above in (3), that is, the external safety device 2 to the motor control device 1 are mutually Equipment must be provided to monitor and diagnose matches.

In other words, the safety monitoring device 16 is a device responsible for monitoring and diagnosing whether the external safety device 2 is operating normally. When the commands (Lo/High) of the multiple safety input signals S1 and S2 sent (inputted) from the external safety device 2 to the motor control device 1 match each other, the safety monitoring device 16 will: It determines that the external safety device 2 is operating normally, and outputs a Lo signal (diagnostic protection signal Sd=Lo).

Further, when the commands (Lo/High) of the multiple safety input signals S1 and S2 sent (input) from the external safety device 2 to the motor control device 1 do not match each other, the safety monitoring device 16 It determines that the safety device 2 or the transmission system is not operating normally, and outputs a High signal (diagnostic protection signal Sd=High).

Conventionally, the safety monitoring device as described above has been used as an external device similar to the external safety device 2, that is, as an external device of the motor control device 1, exclusively during maintenance of the processing equipment system, so that each part is in a normal condition. I was diagnosing whether it works or not. As such a safety monitoring device, for example, a device using a signal monitoring method called EDM (External Device Monitoring) is known.

On the other hand, when the safety monitoring device is used as an external device of the motor control device 1, there is a problem that the wiring to the processing equipment system becomes complicated, and depending on the frequency of maintenance, wiring connection work becomes troublesome. be.

In view of the above problems, each embodiment described below adopts a configuration in which a safety monitoring device is mounted as an internal device of the motor control device 1. For convenience of explanation, the safety monitoring device 16 will be replaced with the safety monitoring unit 16 in the following description.

<<Embodiment 1>>
FIG. 1 is a diagram illustrating a configuration example of a motor control device according to Embodiment 1 of the present disclosure. A configuration example for controlling a three-phase AC motor will be described below as a specific example, but the present invention is not limited to this and can be applied to control of various other motors.

In addition, the safety functions of mechanical drive systems using motors are defined in multiple international standards (typically IEC61800-5 group). can be applied to the safety functions of Embodiments 1 and 2 described below will be described on the assumption that safe torque off (STO), which is an example of a safe stop operation, is controlled.

As shown in FIG. 1, the motor control device 1 is connected to an external safety device 2, a motor 3, and a three-phase AC main power supply 5 (hereinafter simply referred to as AC main power supply 5). Various blocks (circuits) are provided to control the shaft (the encoder 4 is provided).

Here, the main functional blocks (circuits) included in the motor control device 1 are a safe torque off circuit (STO) 10, a three-phase inverter 11, an AC/DC conversion circuit 12, a current detector 13, and a motor control calculator 14. , a control pulse generator (PWM) 15 and a safety monitor 16 .

<Connections with external blocks, etc.>
Among the above, the AC/DC conversion circuit 12 is connected to the AC main power supply 5 , converts the three-phase AC input from the AC main power supply 5 into DC, and supplies the converted DC power to the three-phase inverter 11 . The AC main power supply 5 is, for example, an external power supply such as a commercial three-phase 200V AC.

The three-phase inverter 11, as shown in FIG. 1, includes a switch circuit having six switches (U, V, W and X, Y, Z) that can be turned on/off. are connected to the three terminals of

The three phases of the three-phase inverter 11 are hereinafter referred to as the U-phase, V-phase, and W-phase, respectively. Symbols are assigned, and symbols X, Y, and Z are assigned to each of the lower switches (arms) in the figure.

The switches U, V, and W of each phase of the three-phase inverter 11 are connected in parallel to the output line of one pole (for example, the positive pole) of the AC/DC conversion circuit 12 and connected to the corresponding phase (terminal) of the motor 3. It is The switches X, Y, and Z of the three-phase inverter 11 are connected in parallel to the output line of the other pole (for example, the negative pole) of the AC/DC conversion circuit 12 and connected to the corresponding pole (terminal) of the motor 3. ing. Further, the switch U and the switch X are connected in series with each other and connected to the same pole of the motor 3 (the lowest terminal in FIG. 1). Similarly, switch V and switch Y are connected in series with each other and connected to the same pole of motor 3 (the second terminal from the top in FIG. 1). Similarly, switch W and switch Z are connected in series with each other and connected to the same pole of motor 3 (top terminal in FIG. 1).

The three-phase inverter 11 having such switch circuits (a plurality of switches) can be realized by power semiconductors. The three-phase inverter 11 selectively turns on the switch U/X, the switch V/Y, and the switch W/Z according to the control pulse signal output from the control pulse generator 15 via the safe torque off circuit (STO) 10. A three-phase alternating current is generated by performing a switching operation to The AC current after such switching operation is sent to the motor 3 as a drive current, thereby rotating the motor 3 and operating the corresponding processing equipment.

Based on the basic program and various input signals, the motor control calculation unit 14 calculates a control operation amount for feedback-controlling the operation of the motor 3, generates a control signal indicating the calculated control operation amount, and A control signal is output to the control pulse generator (“PWM” block in FIG. 1) 15 .

More specifically, the motor control calculation unit 14 detects the drive current (voltage waveform, etc.) supplied to the motor 3 through the current detection unit 13 arranged at any two of the three poles of the motor 3. do. The motor control calculation unit 14 also detects the rotation direction, the rotation speed, and the rotation position of the motor (the phase of the rotation shaft) of the motor 3 through the encoder 4 attached to the rotation shaft of the motor 3 . In addition, the motor control calculation unit 14 can input and detect user's operation instructions through an operation input unit (not shown) including switches, levers, and the like of the processing equipment.

Based on the various input signals described above, the motor control calculation unit 14 calculates the difference ( error). Then, the motor control calculation unit 14 calculates a control operation amount (here, the mode of the three-phase alternating current to be supplied) that allows the motor 3 to operate without error corresponding to the basic program and the user's operation instruction, and calculates A control signal indicating the result (hereinafter also simply referred to as a “control operation amount”) is output to the control pulse generator 15 .

The control pulse generation unit 15 performs PWM (Pulse Width Modulation) modulation on the input control signal, and outputs the control pulse signal whose pulse width is modulated to the safe torque-off circuit 10 . The control pulse generator (PWM) 15 converts the pulse width according to the magnitude of the input control operation amount, and passes through a plurality of signal lines (three phases x two poles = six in this example) to each signal line. to generate a control pulse signal. A control pulse generator (PWM) 15 outputs the generated control pulse signal to the three-phase inverter 11 .

　The control pulse generation unit 15 shown in FIG.

, and a pulse width modulation (PWM) scheme is used to generate pulses based on these magnitude relationships. Alternatively, the pulse generation method generated (output) by the control pulse generator 15 may be, for example, a pulse frequency modulation method that adjusts the pulse generation interval based on the magnitude of the control operation amount. Alternatively, as a pulse generation method generated (output) by the control pulse generator 15, the ON/OFF state of each switch (U, V, W, X, V, Z) of the three-phase inverter 11 is defined by vector coordinates. Alternatively, a method of selecting a predetermined vector for each instantaneous value of the control operation amount may be used.

The motor control calculation unit 14 and the control pulse generation unit 15 can be implemented by a microcomputer or the like on which a control program is implemented, or by an analog/digital circuit. The same is true for the safe torque-off circuit 10 and the safety monitoring unit 16, but when configuring a safety system, blocks related to safety functions should be configured separately from others in order to minimize the influence of other functional blocks. is desirable. For example, only the safe torque-off circuit 10 may be an analog/digital circuit, and may be physically separated from hardware such as a microcomputer on which other functions (control program, etc.) are implemented.

A safe torque-off circuit (STO) 10 is a circuit that functions when safely stopping the motor 3 used in the motor control device 1. As shown in FIG. PWM) 15 , safety monitoring unit 16 , and three-phase inverter 11 . Also, the safe torque off circuit (STO) 10 is connected to the motor control calculation block 14 via the control pulse generator (PWM) 15 .

The safe torque-off circuit 10 of the motor control device 1 is located in the middle of the path for transferring the control pulse signal obtained by the control pulse generator 15 to the three-phase inverter 11, and receives a safety input signal separately input from the external safety device 2. The control pulse signal transfer is activated or interrupted based on the contents of the commands of S1 and S2.

In the present embodiment, the safe torque-off circuit 10 transfers (supplies)/blocks the transfer of the control pulse signal supplied from the control pulse generator 15 to the three-phase inverter 11 in accordance with the commands of the safety input signals S1 and S2. (Supply Prohibited) Perform the action.

Specifically, when both of the safety input signals S1 and S2 are execution commands, the safe torque-off circuit 10 determines that it is in a normal operation state, and transfers (supplies) the control pulse signal to the three-phase inverter 11. .

On the other hand, when one of the safety input signals S1 and S2 is a stop command, the safe torque-off circuit 10 determines that a safe stop is necessary, and cuts off (supply) the transfer (supply) of the control pulse signal to the three-phase inverter 11 ( restrict. This cut-off (supply inhibition) operation causes the motor 3 to perform a safe torque off (hereinafter referred to as "STO") operation. More specifically, the STO operation of the motor 3 is realized by turning off the power semiconductor gate (corresponding to each switch shown in FIG. 1) that constitutes the three-phase inverter 11 by interrupting the control pulse signal. .

In one specific example, the safe torque-off circuit 10 receives signals sent from the external safety device 2 and the safety monitoring unit 16 described above, both of the safety input signals S1 and S2 are High, and the diagnostic protection signal Sd is In the case of Lo, the control pulse signal input from the control pulse generator 15 is sent (transferred) to the three-phase inverter 11 as it is.

Therefore, according to this system, during normal operation of various devices to which the motor 3 is attached, the motor 3 rotates according to the type of the device and the user's operation, and the motor is controlled by feedback control. 3 As a result, it is possible to ensure the accuracy of the operation of the equipment.

On the other hand, the safe torque-off circuit 10 operates when at least one of the safety input signals S1 and S2 among the signals sent and input from the external safety device 2 and the safety monitoring section 16 is Lo, or when the diagnostic protection signal Sd is When it is High, the transfer of the control pulse signal input from the control pulse generator 15 is cut off (supply prohibited). In one specific example of this case, the safe torque-off circuit 10 switches off all the switches (U, V, W, X, Y, and Z) are turned off (see FIG. 1).

For convenience of explanation, the High state diagnostic protection signal Sd or the Low state safety input signal S1 (S2) may be referred to as a "current cutoff signal".

As can be understood from FIG. 1, the drive current is no longer supplied to the motor 3 by performing the safe stop control according to the output of the current cut-off signal as described above, so the motor 3 is in operation. In this case, the torque is turned off and the motor rotates only with the remaining power. In fact, due to the frictional resistance of the driving mechanism of various processing equipment connected to the motor 3, the processing equipment is quickly stopped when the motor 3 is in a torque-off state. safety stop.

By the way, the above-mentioned international standards (for example, IEC61508 or ISO13849) show the concept of constructing a safety system with dual inputs and dual outputs. A specific configuration of the blocks is not shown.

Therefore, the present inventor proposes specific configurations of the various blocks described above, as described below.

FIG. 2 is a circuit diagram showing a specific configuration example of the safe torque-off circuit 10. As shown in FIG. From another point of view, FIG. 2 is a diagram for explaining a specific example in which a drive current is not supplied to the motor 3 by inputting a current interruption signal to the safe torque-off circuit 10 .

In the example shown in FIG. 2, the safe torque-off circuit 10 includes a buffer circuit BF0 having a plurality of buffer elements, a gate drive element GD having a plurality (six in this example) of photocouplers, an anode cutoff switch Q1, and Q2. In this example, one end of the buffer circuit BF0 in the safe torque-off circuit STO10 is connected to a reference potential (common) corresponding to 0V. A power supply potential of a constant voltage power supply (not shown) is connected to the other end of the buffer circuit BF0 and one end of the anode cutoff switches Q1 and Q2.

From the standpoint of fail-safe, for example, in preparation for disconnection of the signal lines of the safety input signals S1 and S2, the signs and constants of the signals should be changed so that the motor control device 1 reaches the STO operation in the base state of this system. The level of the reference voltage applied by the voltage source may be chosen.

The buffer circuit BF0 determines whether or not to output control pulse signals input from the control pulse generation unit 15 through six signal lines (in other words, for six switches) to a subsequent stage for diagnostics input from the safety monitoring unit 16. It plays a role of switching by the protection signal Sd.

Specifically, the buffer circuit BF0 includes (six) amplifying and inverting elements that amplify and invert the currents of the six signal lines to which the control pulse signal is input, and an inverting and amplifying element that inverts and amplifies the diagnostic protection signal Sd. and an element. A signal line is connected to the buffer circuit BF0 so that the output of the inverting amplifying element is input to each of the six amplifying inverting elements (preceding stage of the inverting section). Also, the outputs of the six amplifying and inverting elements are connected to the cathodes of the light emitting diodes in the optocouplers of the gate drive elements GD that operate the corresponding switches (U, V, W, X, Y, and Z) of the three-phase inverter 11. It is connected.

In the state shown in FIG. 2, the anode cutoff switches Q1 and Q2 are off and no current is supplied to the light emitting diode of the gate drive element GD, so no current is output from any photocoupler. As a result, the corresponding switches (U to Z) of the three-phase inverter 11 are also turned off (see FIG. 1 as appropriate), and no drive current is supplied to the motor 3 .

Moreover, even if one anode cutoff switch Q1 (or Q2) is turned on based on the safety input signal (either S1 or S2) from the state shown in FIG. ) is off, no current is supplied to the light-emitting diode of the corresponding gate drive element GD, and no current is output from the corresponding photocoupler. As a result, the corresponding three switches U, V, and W (or X, Y, and Z) of the three-phase inverter 11 are also in an off state, and no drive current is supplied to the motor 3 .

In the present embodiment, when only one anode cutoff switch Q1 (or Q2) is turned on for a certain period of time, all the switches of the three-phase inverter 11 are turned on because the diagnosis protection signal Sd goes high. (U to Z) are turned off, and no drive current is supplied to the motor 3 . A specific circuit configuration and the like for realizing this operation will be described later with reference to FIG.

On the other hand, when both anode cutoff switches Q1 and Q2 are turned on based on the safety input signals S1 and S2 from the state shown in FIG. It will be ready for supply. In this case, the on/off state or switching of the corresponding switches (U to Z) of the three-phase inverter 11 according to the presence or absence of light emission of each light emitting diode of the gate drive element GD and the output current of each photocoupler is determined by the buffer circuit. It is determined by the output (Lo/High) from the corresponding amplifying and inverting element of BF0.

In this example, when a High signal is input from the control pulse generator 15 and a Lo signal is output from the amplifying/inverting element of the buffer circuit BF0, the corresponding light-emitting diode of the gate drive element GD emits light, and the corresponding photocoupler , the corresponding switch (any one of U to Z) of the three-phase inverter 11 is turned on. Conversely, when a Lo signal is input from the control pulse generator 15 and a High signal is output from the amplifying/inverting element of the buffer circuit BF0, the corresponding light-emitting diode of the gate drive element GD does not emit light, and the corresponding photocoupler , the corresponding switch (any one of U to Z) of the three-phase inverter 11 is turned off.

Furthermore, when the diagnosis protection signal Sd input to the enable terminal (inverting amplification element) is High, it is inverted to a Lo signal by the inversion amplification element, and the Lo signal is input to all the amplification inversion elements of the buffer circuit BF0. Outputs of all amplifying and inverting elements become High due to the inverting process. As a result, none of the light emitting diodes of the gate drive element GD emit light, none of the photocouplers output current, and all switches (U to Z) of the three-phase inverter 11 are turned off.

Thus, according to the circuit configuration shown in FIG. 2, based on the safety input signals S1 and S2 (instructions), current can be supplied to all the light emitting diodes, and the diagnosis protection signal Sd is Lo. (In other words, a drive current is supplied to the motor 3 on condition that the safety stop command is not sent).

On the other hand, when any photocoupler of the gate drive element GD is in the ON state and the diagnostic protection signal Sd input to the inverting amplifier element of the buffer circuit BF0 becomes Hi, the signal of Hi applied by inverting amplification becomes Lo. , and input to each amplifying/inverting element of the buffer circuit BF0. As a result, the output of the control pulse signal input from the control pulse generator 15 through each signal line to the subsequent stage (gate drive element GD) is blocked, and all the photocouplers of the gate drive element GD are turned off. . Therefore, in this case, all the switches (U to Z) of the three-phase inverter 11 are in an off state (see FIG. 1 as needed), and the drive current is not supplied to the motor 3 (cut off).

Thus, according to the circuit example shown in FIG. 2, a plurality of (six in this example) pulse signals output from the control pulse generator 15 pass through the buffer element BF0 and the gate drive element GD in order to the three-phase inverter. 11 respectively. Then, the three-phase inverter 11 transmits (supplies) alternating current to the motor 3 connected to the outside of the motor control device 1 by switching the built-in power semiconductor.

When the diagnosis protection signal Sd is lost, the enable terminal of the buffer element BF0 is turned off, and as a result, the light emission of the light emitting diodes of all the photocouplers (U to Z) of the gate drive element GD is cut off. In addition, the configuration is such that safe torque off of the motor 3 can be realized.

<Modifications, etc.>
Buffer element BF0 may be a multi-channel element. Also in this case, an enable terminal capable of turning ON/OFF the output of each channel of the buffer element BF0 may be provided, and the diagnosis protection signal Sd may be input to the enable terminal.

As for the gate drive element GD, the circuit configuration using a photocoupler has been described in FIG. As another example, the gate drive element GD is an element capable of switching between transfer/transfer inhibition (blocking) of each pulse signal input from the control pulse generator 15, such as an optical coupler. or an element incorporating a magnetic coupler. Furthermore, as another example, the gate drive element GD is not limited to a configuration in which each pulse signal input from the control pulse generation unit 15 is transferred as it is, and each pulse signal is transferred to each gate of the three-phase inverter 11 ( It may be a circuit that converts to various digital signals for driving the switches (U to Z).

<Safety Monitoring Department>
FIG. 3 shows one specific example of a circuit that makes up the safety monitoring section 16 of the present disclosure. Note that the logic elements in the figure are connected to a constant voltage source (not shown) when driven as an actual circuit, but the description of the constant voltage source is omitted because it does not affect the description of the function.

The safety monitoring unit 16 shown in FIG. 3 branches the safety input signals S1 and S2 sent from the external safety device 2 in parallel to a first processing block B1 and a second processing block B2, respectively, and performs calculations. process. Then, the safety monitoring unit 16 performs a logical sum (OR) operation on the operation output of the first processing block B1 and the operation output of the second processing block B2 in the third processing block B3 to generate a diagnosis protection signal Sd. generate and output .

The first processing block B1 of the safety monitoring unit 16 is configured by sequentially connecting an XOR unit B11, a charging/discharging unit B12, and a latch unit B13 in series from the front side.

Of these, the XOR unit B11 compares the safety input signal S1 and the safety input signal S2, detects whether there is a difference in the polarity of High/Low of these signals, and if there is a difference, outputs a High signal to the subsequent stage. to output The XOR section B11 corresponds to the "comparison section" of the present disclosure. For example, as shown in FIG. 3, the XOR unit B11 includes an XOR element X1 that performs a logical XOR operation of the safety input signal S1 and the safety input signal S2, and a resistor R11 that pulls down the result of the operation (that is, the output of the XOR element X1). and can be composed of Here, the pull-down resistor R11 corresponds to the "first resistor" of the present disclosure.

In the following, a resistor having an equivalent function will be referred to as a "pull-down resistor", and a resistor that plays the opposite role of pulling up the output will be referred to as a "pull-up resistor".

One end of the pull-down resistor R11 is connected to the output ends of the XOR element X1 and the XOR section B11, and the other end of the pull-down resistor R11 is connected to the reference potential. Such a pull-down resistor R11 has a role of, for example, lowering the output potential of the XOR unit B11 to the reference potential when the safety monitoring unit 16 is activated, and stabilizing the output value. is.

Next, the charging/discharging unit B12 plays a role of a timer that stores information on the duration of the difference by charging the high current output when the difference is detected by the XOR unit B11. . As such a charging/discharging unit B12, for example, as illustrated in FIG. .

Here, the resistor R12 corresponds to the "second resistor" of the present disclosure. One end of the resistor R12 is connected to the output end of the XOR element (X1), and the other end of the resistor R12 is connected to the output end of the charging/discharging section B12.

Further, the capacitor C11 has a role of charging and discharging the current supplied to the charging/discharging section B12, and one end (positive voltage terminal) of the capacitor C11 is connected to the other end of the resistor R12 and the output terminal of the charging/discharging section B12. , and the other end of the capacitor C11 is connected to the reference potential.

In addition, in the example shown in FIG. 3, a circuit of series-connected diode D11 and resistor R13 (hereinafter also referred to as a diode circuit) is connected in parallel from the output side of resistor R12 to the input side. Here, the resistor R13 corresponds to the "third resistor" of the present disclosure. The magnitude relationship between the resistance values of the resistor R12 (second resistor) and the resistor R13 (third resistor) is R12>R13.

The above diode circuit does not function when charging the capacitor C11 (the circuit with only the resistor R12 functions), and functions as a parallel resistance circuit of the resistors R12 and R13 when discharging the capacitor C11. Therefore, the difference in the resistance values of the resistors R12 and R13 allows the charging and discharging currents (time constants) to be adjusted to different values.

The charging/discharging unit B12 having such a configuration charges the capacitor C11 (charge accumulation) when the output of the preceding XOR unit B11 changes from Low to High (in other words, when there is a difference between the signals S1 and S2). to start. Then, when the output of the XOR unit B11 returns to Low before the charge accumulated in the capacitor C11 reaches the threshold value (in other words, when there is no difference between the signals S1 and S2), the charge/discharge unit B12 The capacitor C11 (in other words, the timer) is reset by discharging the charge accumulated in the capacitor C11 to the resistors R11, R12, and R13.

On the other hand, in the charging/discharging section B12, when the output of the XOR section B11 remains High for a certain period of time, charges are accumulated in the capacitor C11, and the voltage of the capacitor C11 gradually approaches the output voltage of the XOR section B11.

Furthermore, the latch unit B13 has a function of determining whether or not the voltage of the capacitor C11 exceeds a predetermined voltage threshold, and holding (continuously outputting) the determination result as a High state output when the voltage exceeds the predetermined voltage threshold. . If the voltage of the capacitor C11 is regarded as a timer, this action can be said to have the same effect as determining whether or not the duration of the difference between the safety input signal S1 and the safety input signal S2 has exceeded a predetermined time limit. Note that the charge/discharge unit B12 and the latch unit B13 correspond to the "latch unit" of the present disclosure. Also, hereinafter, the output of the latch section B13 will be referred to as a signal SL.

For example, as shown in FIG. 3, the latch section B13 includes a logical OR element O11 and a pull-down resistor R14 that pulls down the output of the logical OR element O11.

Optionally, the latch unit B13 also includes a capacitor C12 that stores (charges and discharges) the output of the logical OR element O11. In the latch unit B13, one input of the OR element O11 is connected to the output terminal of the timer unit B12 and the voltage terminal (positive voltage terminal) of the capacitor C11, and the other input of the OR element O11 is connected to the output of the OR element O11. It consists of a direct feedback circuit. Whether or not the voltage of the capacitor C11 exceeds the threshold is determined using the high-level voltage, which is the characteristic value of the logical OR element O11, as a threshold.

The second processing block B2 detects (determines) when both the safety input signal S1 and the safety input signal S2 indicate an operation permission state (for example, High) of the motor 3, and determines the detection result (operation permission state). If Lo) is output. For example, as shown in FIG. 3, the second processing block B2 includes a NAND element N1 for calculating a logical NAND of the safety input signal S1 and the safety input signal S2, a resistor R21 for pulling up the output of the NAND element N1, Consists of

The third processing block B3 includes an OR element O3 that performs a logical sum (OR operation) of input signals, and a pull-up resistor R3 connected to the output end of the OR element O3 and the output side of the third processing block B3. , provided. The input end of the OR element O3 is connected to the output end of the first processing block B1 and the output end of the second processing block B2, respectively.

Thus, the safety monitoring unit 16 ORs the output of the first processing block B1 and the output of the second processing block B2 using the OR element O3 of the third processing block B3, and outputs the result of the OR operation (Lo or High ) as the diagnostic protection signal Sd. Then, the low or high diagnostic protection signal Sd output from the safety monitoring unit 16 is input to the enable terminal of the buffer element BF0 (see FIG. 2) in the safe torque-off circuit 10 in the subsequent stage.

Hereinafter, similarly, the case where the diagnosis protection signal Sd is in the Lo state will be described as the operation permission state of the motor 3 . In this case, the first processing block B1 outputs a Lo signal by operating the pull-down resistors R11, R14, etc. at startup. After that, in the first processing block B1, a difference occurs between the safety input signal S1 input from the external safety device 2 and the safety input signal (the output of the XOR section B11 becomes High), and the difference becomes a predetermined value. When the time elapses, the high diagnostic protection signal Sd is continuously output.

The output of the second processing block B2 will be Lo when both the safety input signals S1 and S2 are High (operation permitted state). Also, the third processing block B3 outputs the logical OR of the output of the first processing block B1 and the output of the second processing block B2 as the diagnosis protection signal Sd.

Therefore, the safety monitoring unit 16 outputs a signal different from the normal signal (detects an abnormality between the signals S1 and S2) only when the first processing block B1 determines that the difference has continued for a certain period of time. )be able to.

As described above, in this embodiment, the drive current is sent to the motor 3 to bring the motor 3 and the processing equipment into the normal operation state, and the safety input signal S1 related to the safety function operation of the processing equipment sent from the external safety device 2 , S2 (multiplexed commands), the motor control unit ( A safety monitoring unit 16 (command monitoring unit ) is built in.

As described in detail with reference to FIG. 3, the safety monitoring unit 16 (command monitoring unit) causes the motor 3 to safely stop ( A safe stop command (diagnostic protection signal Sd=High) for STO) is generated, and the generated safe stop command (High diagnostic protection signal Sd) is sent to the motor control unit (safe torque off circuit 10).

Specifically, the safety monitoring unit 16 (command monitoring unit) includes an XOR unit B11 (comparison unit) that compares the respective safety input signals S1 and S2 (command) and outputs the difference as a High signal, and a High signal A power storage unit (charging/discharging unit B12) that accumulates electric charge, and a safe stop command generation unit (charging/discharging unit) that generates and outputs a safety stop command (High diagnostic protection signal Sd) when the voltage of the power storage unit exceeds a threshold value. B12 and a latch portion B13).

In the motor control device 1 of the present embodiment having the safety monitoring unit 16 as described above, the safety input signal S1 and the safety input signal S2 are inputted and compared with each other, and one of these two inputs (S1, S2) , the abnormality can be detected and the STO of the operation of the motor 3 can be operated.

Further, according to the present embodiment in which the safety monitoring unit 16 is incorporated as an internal device of the motor control device 1, it is possible to monitor whether the external safety device 2 is operating properly without using an external monitoring device. In other words, monitoring can be performed without wiring. Therefore, there is an advantage that the safety design of the motor control device 1 and the processing equipment system as a whole, which incorporates a monitoring function for monitoring multiple safety input signals and detecting abnormalities, is facilitated.

Furthermore, the power storage unit (charge/discharge unit B12) of the safety monitoring unit 16 (command monitoring unit) secures the time from when the XOR unit B11 (comparison unit) outputs a High signal until the voltage of the capacitor C11 exceeds the threshold. An RC time constant circuit (R12 and C11) is provided to charge capacitor C11 as follows. The safety stop command generation unit also includes a latch unit B13 that holds the output of the safety stop signal (High diagnostic protection signal Sd) when the voltage of the capacitor C11 exceeds the threshold (discharged from the capacitor C11).

The RC time constant circuit (R12 and C11) as described above can perform the same function as a general timer that measures time based on, for example, a clock signal, and can be realized at low cost.

From another point of view, the safety monitoring unit 16 (command monitoring unit) sends the multiplexed commands (safety input signals S1, S2) to the first processing block B1 (first signal processing unit) and the second processing block B1 (first signal processing unit), respectively. branched in parallel to the signal processing unit B2 (second signal processing unit), and based on the logical sum (OR) of the calculation output of the first processing block B1 and the calculation output of the second processing block B2, safe torque off The following diagnostic protection signal Sd is output to the circuit 10 (motor controller).

That is, the safety monitoring unit 16 uses the above-described timer function to send Lo as the diagnostic protection signal Sd when the period in which the safety input signals S1 and S2 (multiplexed commands) do not match each other does not exceed the allowable value. Then, when the period of non-coincidence exceeds the allowable value, Hi (safety stop command) is sent as the diagnosis protection signal Sd.

As a specific example of a circuit configuration for outputting the diagnostic protection signal Sd as described above, the first processing block B1 (first signal processing section) includes an XOR section B11, a charge/discharge section B12, and a latch section B13. are serially connected in order, and the second processing block B2 (second signal processing section) is provided with a NAND section that performs NAND operations on the safety input signals S1 and S2 (multiplexed commands) and outputs them.

Specifically, the XOR unit B11 includes an XOR element X1 that outputs an exclusive OR of the safety input signals S1 and S2 (multiplexed instructions), and a first resistor (R11) that pulls down the output of the XOR element X1. And prepare.

The charge/discharge unit B12 is an RC time constant circuit composed of a second resistor (R12) one end of which is connected to the output end of the XOR element X1, and a capacitor C11 connected to the other end of the second resistor (R12). and charges the capacitor C11 when the output of the XOR element X1 is High, and discharges the capacitor C11 when the output of the XOR element X1 is Low.

Further, the latch section B13 includes an OR element O11 whose first input terminal is connected to the output terminal of the RC time constant circuit (R12, C11), and a pull-down resistor (R14) that pulls down the output of the OR element O11. , and the output of the OR element O11 is directly connected to the second input terminal of the OR element O11.

Furthermore, the NAND section B2 of the second processing block B2 (second signal processing section) includes a logical NAND element (N1) for calculating and outputting a negative logical product (NAND) of the commands (S1, S2), and a resistor (R21) that pulls up the output of the logic NAND element (N1).

By adopting the circuit configuration described above, it is possible to switch the diagnostic protection signal Sd between Lo and Hi (safety stop command). Further, by adopting the circuit configuration described above, it is possible to provide ancillary functions for coping with various technical problems to be described later.

As described above, according to the present embodiment, a motor control system such as an inverter circuit for driving and controlling the motor 3 is equipped with a monitoring function of a multiple system safety system and a protection function according to the monitoring result. It is possible to more easily construct a safety system in a system of industrial machines such as processing equipment that uses

The main circuit configuration and operation of the safety monitoring unit 16 shown in FIG. 3 have been described above. Next, ancillary functions of the safety monitoring unit 16 shown in FIG. 3 and advantages obtained from the functions will be described.

<Problem in charging/discharging unit B12 and corresponding configuration>
When the safety input signal S1 and the safety input signal S2 are input to the first processing block B1 of the safety monitoring unit 16, the XOR unit B11 frequently switches the output (High/Lo) of the XOR element X1. can. Such a case is, for example, a case where the difference between these two safety input signals (S1, S2) repeatedly occurs instantaneously due to some factor such as an error or minute noise.

Thus, when the frequency of switching the output (High/Lo state) of the XOR element X1 is high, depending on the configuration of the capacitor C11 in the subsequent charging/discharging section B12, particularly when the discharge time constant of the capacitor C11 is large, the following problems may occur. can occur. That is, since the time for which the output of the XOR element X1 remains in the Lo state is shortened, the charge in the capacitor C11 of the charging/discharging section B12 is not sufficiently discharged, and the output of the XOR element X1 repeatedly becomes High, thereby The voltage rise characteristics of C11 may become uneven.

In order to deal with the above problem, it is required to improve the discharge characteristics of the capacitor C11 in the charging/discharging section B12. Also, in order to improve the discharge characteristics while maintaining the accuracy of the timer measurement time described above, it is necessary to make the discharge time constant smaller than the charge time constant of the capacitor C11.

Regarding this problem, in this embodiment, as shown in FIG. A configuration in which the anode side of D11 is connected to capacitor C11 is adopted.

According to this configuration, the resistance value of the resistor R11 of the XOR unit B11 and the resistance value of the resistor R13 of the charging/discharging unit B12 are sufficiently smaller than the resistance value of the resistor R12 of the charging/discharging unit B12. The discharge time constant can be made smaller than the constant, and the discharge time can be shortened.

Therefore, according to the circuit configuration of the first processing block B1 in this embodiment, it is possible to improve the discharge characteristics of the capacitor C11 while maintaining the accuracy of the timer measurement time described above. Further, according to this circuit configuration, even when the frequency of switching the output (High/Lo state) of the XOR element X1 is high, the voltage rise characteristic of the capacitor C11 can be maintained.

<Problem in Latch Unit B13 and Corresponding Configuration>
Since the logic OR element O11 of the latch section B13 has a circuit configuration in which once the output is set to High, it continues to output High, it is necessary to be careful of malfunction due to mixing of noise or the like.

Regarding this problem, in this embodiment, as shown in FIG. 3, a configuration is adopted in which a capacitor C12 is connected in parallel to the output of the OR element O11. With such a configuration, when noise or the like is mixed, the noise component can be absorbed by the capacitor C12, so malfunction caused by the noise or the like can be prevented or suppressed.

<<Embodiment 2>>
FIG. 4 is a configuration example of a safe torque-off circuit according to Embodiment 2 of the motor control device of the present disclosure. The configuration shown in FIG. 4 is an alternative to the safe torque off circuit 10 shown in FIG. 2 described above.

　Hereinafter, matters different from the safe torque-off circuit 10 shown in FIG. 2 will be described, and the same reference numerals will be assigned to the same configurations, and the description thereof will be omitted as appropriate. Similarly, the description of the constant voltage source connected to the logic element is omitted.

2 and 4, the safe torque-off circuit 10A shown in FIG. 4 has the anode cutoff switches Q1 and Q2 removed from the configuration shown in FIG. A1 and a logical AND element A2 have been added.

In general, the main difference between the safe torque-off circuit 10A shown in FIG. 4 and the configuration shown in FIG. and the series connection of buffer element BF1 and buffer element BF2. With such a configuration, the safe torque-off circuit 10A shown in FIG. 4 can achieve safe torque-off of the dual system motor.

2, the safe torque-off circuit 10A is configured so that the STO operation can be performed even by the diagnostic protection signal Sd. are branched and connected to each other.

In the example shown in FIG. 4, the output terminals of the logic AND elements A1 and A2 are connected to the enable terminals of the buffer elements BF1 and BF2 to which the diagnosis protection signal Sd is input. Signal lines for the safety input signal S1 and the safety input signal S2 are connected to one ends of the inputs of the logic AND element A1 and the logic AND element A2. Further, the other terminals of the inputs of the logical AND element A1 and the logical AND element A2 are respectively provided with inverting portions so that the inverted signal of the diagnosis protection signal Sd is input (see FIG. 4 as appropriate).

According to the safe torque-off circuit 10A configured as described above, when the operation is similar to that of FIG. signal is output. The operation of each signal (S1, S2, Sd) other than the above is the same as in the case of FIG. 2, and a detailed description thereof will be omitted.

<<Embodiment 3>>
FIG. 5 is an example of a motor control device according to Embodiment 3 of the motor control device of the present disclosure. The motor control device 1A shown in FIG. 5 not only monitors the difference between the safety input signal S1 and the safety input signal S2 by the safety monitoring unit 16, but also checks whether the safety monitoring unit 16 that performs such monitoring functions normally. It has a function that can be inspected. Differences from the motor control device 1 described above with reference to FIG. 1 will be described below.

In Embodiment 3, it is assumed that a monitor device 2B such as an image display is used as an external device of the motor control device 1A. 5 is equivalent to the external safety device 2 shown in FIG.

The motor control device 1A of Embodiment 3 includes test switches QT1 and QT2 capable of blocking transmission of the respective signals (S1 and S2) on the transmission paths of the safety input signal S1 and the safety input signal S2. In the state shown in FIG. 5, these test switches QT1 and QT2 are both ON. Further, in Embodiment 3, the ON/OFF of these test switches QT1 and QT2 can be operated by the motor control calculation section 14A. Further, the motor control calculation section 14A of Embodiment 3 is configured to detect the state of the diagnostic protection signal Sd output from the safety monitoring section 16. FIG.

Specifically, the motor control calculation unit 14A additionally includes an operation unit 142 that outputs a signal for turning on/off the test switches QT1 and QT2. This operation unit 142 has a function of operating so that at least one of the multiple commands (S1, S2) is not sent to the motor control unit (safe torque off circuit 10 in this example).

The motor control calculation unit 14A also includes a notification unit 141 that notifies the external monitor device 2B of the diagnosis protection signal Sd, the state of the device, etc. based on the diagnosis protection signal Sd transmitted from the safety monitoring unit 16. In the illustrated example, the diagnostic protection signal Sd output from the safety monitoring section 16 is also input to the notification section 141 and the operation section 142 . Other configurations (functions) of the motor control calculation unit 14A are equivalent to those of the motor control calculation unit 14 described above with reference to FIG.

The significance and advantages of the circuit configuration shown in FIG. 5 will be described below. For example, in the configuration shown in FIG. 1, if the STO state occurs due to the action of the diagnostic protection signal Sd, although the motor 3 is in a torque-off state due to the STO operation, the cause (in this example, the diagnostic protection signal Sd (whether it was an effect or not) may not be able to be determined.

On the other hand, in the circuit configuration shown in FIG. Since the waveform of the diagnostic protection signal Sd and its transition can be notified to the external monitor device 2B and displayed on the monitor device 2B, there is an advantage that the system user can specify the cause.

In addition, in the circuit configuration shown in FIG. 5, the test switches QT1 and QT2 are configured so that they can be operated from the operation section 142 provided in the motor control calculation section 14A, so there is an advantage that the safety is further enhanced.

More specifically, for example, in a state in which the safety input signals S1 and S2 indicate that the motor operation is permitted, one of the test switches QT1 or QT2 is turned OFF intentionally (for example, by a user's operation) to turn off the safety input. By interrupting the transmission of one of the signals S1, S2, it is possible to check whether the diagnosis protection signal Sd correctly transitions to High. In other words, according to the circuit configuration shown in FIG. 5, it is possible to self-diagnose whether or not the safety monitoring unit 16 is normal, so that a more failure-free safety system can be constructed.

Although the test switches QT1 and QT2 shown in FIG. 5 are illustrated as physical switches that cut off the safety input, the polarity (high/high/high) of the safety input signals S1 and S2 such as pull-down/pull-up are also possible. A similar self-diagnostic function can be achieved with a mechanism that inverts Lo).

<<Embodiment 4>>
FIG. 6 is a circuit diagram showing a configuration example when an electrical input circuit is provided in the transmission path of the safety input signals S1 and S2 in the motor control device according to Embodiment 4 of the present disclosure.

In the example shown in FIG. 6, a first-order lag filter consisting of a resistor RF and a capacitor CF is provided in front of the safety monitoring unit 16 and the safe torque-off circuit 10 in the transmission path of the safety input signals S1 and S2. , is input to the safety monitoring unit 16 and the safe torque-off circuit 10 .

In each first-order lag filter, the output terminal of the resistor RF is connected to one terminal of the capacitor CF and the input terminals of the safety monitoring section 16 and the safe torque-off circuit 10 . Also, the other terminal of the capacitor CF is connected to the reference potential. Furthermore, the time constant of each first-order lag filter is sufficiently larger than the time constant of the RC time constant circuit defined by the resistor R12 (second resistor) and capacitor C11 of the safety monitoring unit (command monitoring unit) 16 described above. set short.

According to the circuit configuration described above, the STO operation can be obtained in the safe torque-off circuit 10 without waiting for the diagnosis (Sd=High) by the safety monitoring unit 16, and the desired response is obtained as the multiple safety input signals S1 and S2. be able to.

<<Embodiment 5>>
FIG. 7 is a diagram according to Embodiment 5, and is a circuit diagram showing an example in which the motor control device of the present disclosure can also be applied to a safety function different from STO.

A motor control device 1B shown in FIG. 7 is additionally equipped with a safety control unit 20, and includes safety input signals S1 and S2, a diagnostic protection signal Sd, and the output of the encoder 4 (rotor position information of the motor 3). is input to the safety control unit 20 . The safety control unit 20 is arranged before the motor control calculation unit 14 and the safe torque off circuit 10 and after the external safety device 2 and the safety monitoring unit (command monitoring unit) 16. and the position of the rotor.

Here, the safety control unit 20 has a function of outputting double deceleration instructions SL1 and SL2 to the motor control calculation block 14. The safety control unit 20 also has a function of outputting double safe stop (STO) instructions ST1 and ST2 to the safe torque-off circuit 10 .

The safety control unit 20 can be realized by analog and digital circuits, software such as a microcomputer, or a combination thereof.

Also, the motor control device 1 may have a configuration in which some functions of the motor control device 1 are separated and added as an option. For example, the safety monitoring unit 16 and the safety control unit 20 shown in FIG. 7 may be optional blocks that can be attached and detached via an interface or the like, separate from the main body (that is, the internal blocks of the motor control device 1). With such a configuration, any type of safety function can be added as required. Therefore, the cost of the main body of the motor control device 1 can be reduced, and the optimum safety function for the motor 3 can be selected according to the type and operation of the motor 3 and the device to which the motor 3 is attached.

In one standard, the safety function SafeStop1 (SS1) is defined as a safe stop function that has a period of deceleration based on a predetermined deceleration pattern as a step prior to torque-off stop at STO. As means for realizing SS1 that ensures such a deceleration period, the safety control unit 20 performs the following control.

When the safety control unit 20 receives a stop command or a safety stop command (Sd=High) from the safety monitoring unit 16 as the safety input signals S1 and S2, it sends double deceleration instructions SL1 and SL2 to the motor control calculation block 14. and begins monitoring the speed of motor 3 based on signals received from encoder 4 . When the speed of the motor 3 becomes equal to or lower than a predetermined speed (threshold speed) as a result of the monitoring, the safety control unit 20 sends an STO instruction to the safe torque-off circuit 10 . Such control prevents the motor 3 from suddenly stopping when the safety input signals S1 and S2 are output, thereby preventing damage to the corresponding equipment and ensuring the safety of workers working with the equipment. security can be ensured or expected.

<<Embodiment 6>>
FIG. 8 shows an example of the internal circuits of the safety control section 20 and the safe torque-off circuit 10 according to the sixth embodiment. In the circuit configuration shown in FIG. 8, the output of the safety control section 20 is logically configured so that ST1 and ST2 become Lo when the diagnostic protection signal Sd is High. STO can work. Even in such a configuration, by utilizing the safety monitoring block 16 and the diagnostic protection signal Sd for diagnosis of the safety inputs S1 and S2, a safety system with fewer failures can be realized.

<<Embodiment 7>>
FIG. 9 shows an example of internal circuits of the safety monitoring unit 16 and the safe torque-off circuit 10 according to the seventh embodiment. In the circuit configuration shown in FIG. 9, inside the safe torque-off circuit 10, second anode cutoff switches Q1D and Q2D are inserted between the outputs of the anode cutoff switches Q1 and Q2 and the anode of the gate drive element GD. .

The second anode cutoff switches Q1D and Q2D are normally ON (hereinafter referred to as "normally on") polarity, and are driven (switched off) by the high output of the diagnostic protection signal SL. It's becoming With this configuration, when a difference is detected between the safety input signal S1 and the safety input signal S2, the diagnosis protection signal SL outputs a high signal, thereby turning off both the second anode cutoff switches Q1D and Q2D. As a result, the motor 3 is in a torque-off state.

Among them, the anode cutoff switches Q1 and Q2, which play a role of cutting off the drive signals supplied to the motor 3 in response to the commands S1 and S2 (safety input signals), correspond to the "first cutoff section" in the present disclosure. . On the other hand, the second anode cutoff switches Q1D and Q2D, which serve to cut off the drive signal supplied to the motor 3 in response to the diagnostic protection signal SL (safety stop signal), are the "second cutoff section" in the present disclosure. handle. In this embodiment, the anode cutoff switch Q1 and the second anode cutoff switch Q1D in the first cutoff section are connected in series, and similarly, the anode cutoff switch Q2 and the second anode cutoff switch Q2 in the first cutoff section are connected in series. and Q2D are connected in series.

Furthermore, in the circuit configuration shown in FIG. 9, the signal to be input to the safety monitoring section 16 is input so as to feed back the output voltage of the second anode cutoff switches Q1D and Q2D (second cutoff section). As described above, the second anode cutoff switches Q1D and Q2D have normally-on polarities. Therefore, while the diagnostic protection signal SL is Low after the device is started, the input to the safety monitoring unit 16 is not for other implementations. Signals corresponding to the safety input signals S1 and S2 are input in the same manner as in the form.

On the other hand, after the safety monitoring unit 16 sets the diagnostic protection signal SL to High, the second anode cutoff switches Q1D and Q2D are turned off, so the inputs to the safety monitoring unit 16 are the safety input signal S1 and the safety input signal S2. Although there is a possibility that the input state of is not reflected, the torque-off state of the motor 3 is maintained by the action of the latch portion B13, so the safety function can be achieved.

In this way, if the safety monitoring unit 16 is configured to feed back the downstream signal as an input of the safety monitoring unit 16 to the part (the second anode cutoff switches Q1D and Q2D in this embodiment) that operates the torque off, FIG. 3, the second processing block B2 and the third processing block B3 are not necessary, which contributes to the miniaturization of the apparatus.

Although the present invention has been described above based on the embodiments, the present invention is only an example of the configuration of the above-described embodiments, and is not limited to this, and various modifications are possible. In the embodiment described above, addition, deletion, replacement, etc. of components are possible except for essential components. Unless otherwise specified, each component may be singular or plural. A configuration in which various configuration examples are combined is also possible.

1, 1A, 1B Motor control device 2, 2A External safety device 2B Monitor device 3 Motor 4 Encoder 5 AC main power supply 10 Safe torque off circuit (motor control unit)
11 3-phase inverter (motor control unit, power semiconductor)
12 AC/DC conversion circuit 13 Current detection unit 14 Motor control calculation unit (motor control unit)
15 control pulse generator (motor controller)
16 Safety Monitoring Department (Command and Monitoring Department)
20 Safety control unit (motor control unit)
141 notification unit 142 operation unit A1, A2 logic AND element B1 first processing block (first signal processing unit)
B2 second processing block (second signal processing unit, NAND unit)
B3 Third processing block S1, S2 Safety input signal (multiple commands)
Sd: diagnostic protection signal Q1, Q2: anode cutoff switch BF0, BF1, BF2: buffer element GD: gate drive element B11: XOR section X1: XOR element, R11: pull-down resistor B12: charging/discharging section R12: resistor (second resistor), C11: capacitor, R12, C11 (RC time constant circuit), D11...diode, R13...resistor, D11, R13 (diode circuit)
B13 Latch part O11... OR element QT1, QT2 Test switch RF, CF First-order lag filter ST1, ST2 Stop (STO) instruction SL1, SL2 Deceleration instruction

Claims (14)

1. A motor that puts the motor into a normal operation state by sending a drive current to the motor, and controls the motor so that the normal operation state goes into a safe stop state in response to a multiple command related to safety function operation sent from the outside. a control unit;
   a command monitoring unit that monitors whether the commands match each other;
   The command monitoring unit generates a safe stop command for safely stopping the motor when a period in which the commands do not match each other exceeds an allowable value, and continuously sends the generated safe stop command to the motor control unit. send out,
   Control device.
2. The control device according to claim 1,
   The command monitoring unit
   a comparison unit that compares each of the commands and outputs a difference as a High signal;
   a storage unit that stores the charge of the High signal;
   a safety stop command generation unit that generates and outputs the safety stop command when the voltage of the power storage unit exceeds a threshold;
   Control device.
3. In the control device according to claim 2,
   The power storage unit includes a capacitor, and includes an RC time constant circuit that charges the capacitor so as to ensure a time from when the High signal is output until the voltage of the capacitor exceeds the threshold,
   The safety stop command generation unit includes a latch unit that holds the output of the safety stop command when the voltage of the capacitor exceeds a threshold,
   When the motor control unit receives the safety stop command, the motor control unit controls to cut off or reduce the drive current supplied to the motor.
   Control device.
4. In the control device according to claim 3,
   moreover,
   A notification unit that notifies an external device of the state of the signal output from the latch unit,
   Control device.
5. In the control device according to claim 4,
   moreover,
   an operation unit that operates such that at least one of the multiple commands is not sent to the motor control unit;
   Control device.
6. The control device according to claim 1,
   The command monitoring unit includes an XOR unit, a charge/discharge unit, and a latch unit connected in series in order,
   The XOR unit includes an XOR element that outputs an exclusive OR of the command, and a first resistor that pulls down the output of the XOR element,
   The charging/discharging unit includes an RC time constant circuit including a second resistor one end of which is connected to the output end of the XOR element and a capacitor connected to the other end of the second resistor, and the output of the XOR element is When the output of the XOR element is High, the capacitor is charged, and when the output of the XOR element is Low, the capacitor is discharged;
   The latch section includes an OR element whose first input terminal is connected to the positive voltage terminal of the capacitor, and a pull-down resistor that pulls down the output of the OR element. is directly connected to the output of the OR element,
   Control device.
7. The control device according to claim 1,
   The command monitoring unit branches the multiplexed command in parallel to a first signal processing unit and a second signal processing unit, respectively, and outputs a calculation output of the first signal processing unit and the second signal. A configuration for sending a High signal as the safe stop command to the motor control unit based on a logical sum with the operation output of the processing unit,
   The first signal processing unit includes an XOR unit, a charging/discharging unit, and a latch unit connected in series in order,
   The second signal processing unit has a NAND unit that performs a NAND operation on the multiplexed instructions and outputs them,
   The XOR unit includes an XOR element that outputs an exclusive OR of the command, and a first resistor that pulls down the output of the XOR element,
   The charging/discharging unit includes an RC time constant circuit including a second resistor one end of which is connected to the output end of the XOR element and a capacitor connected to the other end of the second resistor, and the output of the XOR element is When the output of the XOR element is High, the capacitor is charged, and when the output of the XOR element is Low, the capacitor is discharged;
   The latch section includes an OR element whose first input terminal is connected to the positive voltage terminal of the capacitor, and a pull-down resistor that pulls down the output of the OR element. is directly connected to the output of the OR element,
   The NAND unit comprises a logical NAND element for computing and outputting a negative logical product of the command, and a pull-up resistor for pulling up the output of the logical NAND element.
   Control device.
8. In the control device according to claim 7,
   The charging/discharging unit of the first signal processing unit includes a series circuit of a third resistor and a diode connected in parallel to the second resistor,
   The diode has an anode connected to the output terminal side of the second resistor and a cathode connected to the input terminal side of the second resistor. rectifying the section in a discharging direction through the third resistor;
   Control device.
9. In the control device according to claim 7,
   A delay filter circuit is provided before the motor control unit and the command monitoring unit,
   the time constant of the lag filter circuit is shorter than the time constant of the RC time constant circuit;
   Control device.
10. The control device according to claim 1,
    The motor control unit
    A motor control calculation for inputting the drive current supplied to the motor and the position of the rotor of the motor, calculating a control operation amount for correctly operating the motor, and outputting the calculated control operation amount. Department and
    a power semiconductor having a switch circuit that adjusts the drive current sent to the motor based on the control operation amount from the motor control calculation unit;
    a safety stop control unit that performs control to reduce the drive current sent to the motor in response to the safety stop command;
    Control device.
11. A control device according to claim 10, wherein
    The safe stop control unit is provided after the motor control calculation unit and before the power semiconductor,
    transferring the control operation amount signal to the power semiconductor when the safe stop command is not generated from the command monitoring unit;
    When the safety stop command is generated from the command monitoring unit, the switch circuit of the power semiconductor is turned off by interrupting the transfer of the signal of the control operation amount, and the drive current sent to the motor is stopped. Cut off,
    Control device.
12. A control device according to claim 11, wherein
    Furthermore, a safety control unit is provided before the safe stop control unit and the motor control calculation unit, and inputs the multiple command, the signal from the command monitoring unit, and the position of the rotor,
    When the safety stop command is generated from the command monitoring unit, the safety control unit performs control to gradually decrease the drive current sent to the motor based on the rotational movement of the motor, and then controls the motor. perform control to cut off the drive current sent to
    Control device.
13. In the control device according to claim 6,
    The safe stop control unit
    A first interrupter for interrupting the drive current supplied to the motor in response to the command and a second interrupter for interrupting the drive current supplied to the motor in response to the safety stop command are connected in series. , the output of the circuit is input to the XOR unit of the command monitoring unit, and the output of the latch unit of the command monitoring unit is supplied to the second interrupting unit as the safe stop command. is,
    performing control to reduce the drive current sent to the motor in response to the command and the safety stop command;
    Control device.
14. The control device according to claim 1 is connected,
    powered by a motor controlled by the controller;
    processing equipment.

Images